(a) Field of the Invention
The present invention relates to an encryption method, and more particularly, to a method and a system for an additive homomorphic encryption scheme with operation error detection functionality.
(b) Description of the Related Art
A homomorphic encryption is a technology of performing an operation for encrypted data based on published information such as a public-key, without plaintext information or secret information on the encrypted data. In detail, even though plaintext data corresponding to a ciphertext are not known, the homomorphic encryption technique is an encryption technique of performing a series of data processing on the ciphertext to apply the operation to the encrypted plaintext data, thereby performing various data processings on the encrypted data without damaging confidentiality of the encrypted information.
Various studies on the homomorphic encryption technique have been made. At an early stage of the researches, limited techniques of preserving only operations of addition or multiplication in the encrypted state have been proposed to raise an interest in direction in which both the two operations may be preserved. Until recently, there is a general recognition that it is difficult to preserve all the operations
As only a technique of preserving both of the two operations, a technique based on a pairing operation defined in an elliptic curve has been proposed but has a problem in that the multiplication times is limited once.
Recently, a technique of safely providing the two operations is first designed by Gentry in 2009. Various studies for providing theoretical safety, improving implementation performance, providing application services, or the like using the homomorphic encryption technique based on the Gentry's design scheme have been progressed. However, the new design scheme by the Gentry has a radical limit in performance and therefore may be hardly applied to application environment practically. Therefore, a study on the technology of providing performance that may be practically applied to the application environment has been actively conducted again.
In fact, there are a large number of services that may be provided even when only the addition operation is provided are present in the application environment under which the processing on the encrypted data is performed. In addition, since the Gentry's design scheme has a practical problem in the technology development and a necessity for the practical technology is increased, a demand and a study for the practical technology that may be applied to the practical services as described above are getting increased.
As the study on the homomorphic encryption is getting progressed, there is a need to verify whether information processed based on the data stored in the encrypted state is correctly generated. That is, a method for verifying an error that may occur for various reasons during a computation process is required. However, it is not yet easy to provide the operation at realistic costs in the encrypted state and a necessity for an error detection technology has been recognized but technical solutions are not yet present. In future, a technology of storing the data in the encrypted state when being outsourced, providing various data processing services based on the stored data, and detecting an error occurring during the encrypted data processing to improve reliability of the provided service is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.